1. Field of the Invention
The present invention relates to a debarking machine for debarking the bark of wood, and, more particularly, to a novel debarking machine which has a line of rotary members or plural lines of rotary members coupled in series and which is so designed that the inclined angle of the first rotary member located on the wood-infeeding side is set greater than the inclined angle of the n-th rotary member located at the wood-outfeeding side end, and the inclined angles of the second to (n-1)-th rotary members are set within a range from the inclined angle of the n-th rotary member to the inclined angle of the first rotary member and are each set equal to or greater than the inclined angle of the adjoining rotary member which is located on the wood-infeeding side, whereby the staying of wood on the wood-infeeding side and the shortage of wood on the wood-outfeeding side are prevented and the amount of wood per unit length becomes uniform over the entire process from the wood-infeeding side to the wood-outfeeding side, thus ensuring a smooth rotational motion of wood and preventing damage to the wood and insufficient debarking to thereby improve the overall debarking efficiency.
2. Description of the Related Art
One example of debarking machines is illustrated in FIGS. 10 and 11. The debarking machine shown in FIG. 1 has three debarking units 301 coupled in series. A loading hopper 303 is attached to the right debarking unit 301 in FIG. 10. Wood 305 is loaded into the right debarking unit 301 in FIG. 10 via this loading hopper 303.
Rotatably accommodated in each debarking unit 301 are rotors 307 and 309 each having a debarking blade 306 on the outer surface, as shown in FIG. 11. The rotor 309 is disposed farther from the rotor 307 in FIG. 10.
As the loaded wood 305 is moved leftward in FIGS. 10 and 11 on the rotating rotors 307 and 309, its bark is debarked by the debarking blade 306. The left debarking unit 301 in FIG. 10 is provided with a wood-discharge chute 311 through which the debarked wood 305 is discharged. The discharged wood 305 is conveyed by a wood-discharge conveyor 313.
The debarking operation will now be described in detail. FIG. 11 illustrates the interior of the debarking machine. Plural pieces of wood 305 are put on the rotors 307 and 309 and are revolved in the direction indicated by an arrow B in FIG. 11 while rotating in the direction of an arrow A in FIG. 11 in accordance with the rotations of the rotors 307 and 309. Accordingly, the lower wood 305 moves upward and the upper wood 305 comes downward, so that all the pieces of wood 305 evenly hit on the debarking blades 306 of the rotors 307 and 309. This motion is called the "rotational motion of wood." The "rotational motion of wood", if it is smooth, results in efficient debarking. As the "rotational motion of wood" takes place, the pieces of wood 305 are gradually moved leftward in FIGS. 10 and 11. This movement will now be discussed referring to FIG. 12.
As shown in FIG. 12, the rotors 307 and 309 are inclined downward in the direction toward the woodoutfeeding side from the wood-infeeding side by an inclined angle .alpha.. The wood 305 hits against the debarking blades 306 of the rotors 307 and 309 and is pushed upward in the direction of an arrow C (perpendicular to the rotors 307 and 309) in FIG. 12. The lifted wood 305 falls downward in the vertical direction as indicated by an arrow D in FIG. 12 and thus moves by a distance l. That is, while the lower wood 305 moves upward and the upper wood 305 moves downward, those pieces of wood 305 gradually move in the wood-discharge direction.
This conventional debarking machine has the following problems.
As shown in FIG. 10, the conventional debarking machine is inclined downward by a given inclined angle (.alpha.) from the wood-infeeding side (right side in FIG. 10) to the wood-outfeeding side (left side in FIG. 10). The inclination is for surely feeding loaded wood 305 to the wood-outfeeding side from the wood-infeeding side.
With this structure, however, a considerable amount of wood 305 stays on the wood-infeeding side and the amount of wood 5 on the wood-outfeeding side is reduced as shown in FIG. 10. This impairs the evenness of the overall amount of wood 305 per unit length, so that the wood 305 may be damaged and/or the debarking of the wood 305 becomes insufficient, thus significantly reducing the debarking efficiency.
Another cause for this problem is the irregular loading of wood 305. When a great amount of wood 305 stays on the wood-infeeding side, the rotational motion of wood 305 becomes insufficient and the same portions of the wood 305 hits on the debarking blades 306 more than necessary. Consequently, the wood 305 is damaged. Some wood 305, however, is not properly debarked by the debarking blades 306, thus resulting in insufficient debarking. As there is not much wood 305 on the wood-outfeeding side where the amount of wood per unit length is small, the load of pressing the wood 305 on the debarking blades 306 becomes insufficient and the debarking effect by the friction between pieces of wood 305 decreases, resulting in insufficient debarking.
If a considerable amount of wood 305 remains on the wood-infeeding side and the amount of wood 305 on the wood-outfeeding side is reduced, thus impairing the uniform amount of wood 305 per unit length, the overall debarking efficiency is decreased and the yield is reduced by the damage to the wood 305.
The prior art of this invention is illustrated in, for example, Unexamined Japanese Patent Publication Nos. Sho 61-141507,Hei 3-136805 and Hei 5-50962.